Performance of prognostic models incorporating KRAS mutation status to predict survival after resection of colorectal liver metastases

BACKGROUND

The Genetic And Morphologic Evaluation (GAME) score and modified clinical score (m-CS) are two novel prognostic models that incorporate KRAS mutation status to predict survival after resection of colorectal liver metastases (CRLM). This retrospective cohort study evaluated the performance of these two models.

METHODS

A total of 103 patients who underwent resection of CRLM between 2007 and 2017 and had known KRAS mutation status were included, 39 (37.9%) of whom had KRAS mutated tumours. Complete case analysis of the patients was performed according to the Clinical Risk Score (CRS), m-CS, and GAME score. The primary outcome was overall survival stratified according to low-risk and high-risk scores. Harrell's C-index and Akaike information criterion (AIC) were used to compare the discrimination of the evaluated prognostic models.

RESULTS

The GAME score demonstrated the largest difference in overall survival for patients stratified according to low-risk and high-risk groups. Harrell's C-index values for the CRS, m-CS, and GAME models were 0.583, 0.600, and 0.668, respectively. AIC values for the CRS, m-CS, and GAME models were 441, 439, and 427, respectively.

CONCLUSION

The GAME score outperforms the CRS and m-CS in predicting overall survival after resection of CRLM in patients with known KRAS mutation status.

Proteomic Profiling and Biomarker Discovery in Colorectal Liver Metastases

Colorectal liver metastases (CRLM) are the leading cause of death among patients with metastatic colorectal cancer (CRC). As part of multimodal therapy, liver resection is the mainstay of curative-intent treatment for select patients with CRLM. However, effective treatment of CRLM remains challenging as recurrence occurs in most patients after liver resection. Proposed clinicopathologic factors for predicting recurrence are inconsistent and lose prognostic significance over time. The rapid development of next-generation sequencing technologies and decreasing DNA sequencing costs have accelerated the genomic profiling of various cancers. The characterisation of genomic alterations in CRC has significantly improved our understanding of its carcinogenesis. However, the functional context at the protein level has not been established for most of this genomic information. Furthermore, genomic alterations do not always result in predicted changes in the corresponding proteins and cancer phenotype, while post-transcriptional and post-translational regulation may alter synthesised protein levels, affecting phenotypes. More recent advancements in mass spectrometry-based technology enable accurate protein quantitation and comprehensive proteomic profiling of cancers. Several studies have explored proteomic biomarkers for predicting CRLM after oncologic resection of primary CRC and recurrence after curative-intent resection of CRLM. The current review aims to rationalise the proteomic complexity of CRC and explore the potential applications of proteomic biomarkers in CRLM.

Clinical and molecular profile of young adults with early-onset colorectal cancer: Experience from four Australian tertiary centers

BACKGROUND

Patients with early-onset colorectal cancer (EO-CRC) have unique characteristics. Contemporary data on the pathological and molecular features, and survival of EO-CRC are limited in the Australian context.

AIM

To determine the demographic, histopathological and molecular characteristics of adults with EO-CRC, and their survival.

METHODS

We conducted a retrospective study of adults aged 18-49 years with EO-CRC who were referred to the Illawarra Shoalhaven Local Health District, South Eastern Sydney Local Health District and Royal North Shore Hospital in New South Wales, Australia, between 2014 and 2018.

RESULTS

Of 257 patients included, 94 (37%) patients presented with de novo metastatic CRC, 80% patients had near-average risk family history and 89% had a symptomatic presentation. In 159 patients with nonmetastatic disease at diagnosis, stage III disease (OR 3.88 [95% CI: 1.13-13.3]; p = .03) and the presence of perineural invasion (PNI) (OR 6.63 [95% CI: 2.21-19.84]; p = .001) were risk factors associated with the development of metastatic disease. Among 94 patients with de novo metastatic disease, 43 (43%) and 12 (14%) patients harbored a KRAS or BRAF V600E mutation, respectively. The median overall survival was 29.6 months (95% CI: 20.4-38.7). BRAF mutation was associated with inferior survival (HR 3.00 [95% CI: 1.30-6.94]; p = .01).

CONCLUSION

The prevalence of KRAS and BRAF mutations in our cohort is similar to the overseas experience. Stage III disease at diagnosis, presence of PNI and BRAF mutation are adverse prognostic indicators. A better understanding of the molecular landscape is needed for this patient cohort, so as to better tailor prevention strategies, screening and treatment pathways.

Survival in borderline resectable and locally advanced pancreatic cancer is determined by the duration and response of neoadjuvant therapy

BACKGROUND

Pancreatic cancer is the 8th commonest cancer and the 5th commonest cause of cancer-related death in Australia, with a 9% average 5-year survival. This study aims to investigate the effects of neoadjuvant treatment on overall survival (OS) and recurrence-free survival (RFS) in borderline resectable (BRPC) and locally advanced (LAPC) pancreatic adenocarcinoma followed by curative resection.

MATERIALS AND METHODS

Prospectively-collected demographic, medical, surgical and pathological data of patients with BRPC and LAPC treated with both neoadjuvant therapy (NAT) and surgery at a single tertiary referral centre in Australia were reviewed and analysed.

RESULTS

Between 2012 and 2018, 60 patients, 34 with BRPC and 26 with LAPC, were treated with NAT followed by curative resection. The commonest neoadjuvant chemotherapy regimens were Gemcitabine + Abraxane (51.7%) and FOLFIRINOX (35.0%), with 48.3% of patients additionally receiving neoadjuvant radiotherapy. Median RFS was 30 months and median OS was 35 months. On multivariable analysis, inferior OS was predicted by enlarged loco-regional lymph nodes on initial computed tomography (p = 0.032), larger tumour size post-NAT (p = 0.006) and Common Terminology Criteria for Adverse Events post-NAT toxicity greater than grade 2 (p = 0.015). LAPC patients received more neoadjuvant chemotherapy (p = 0.008) and radiotherapy (p = 0.021) than BRPC and achieved a superior pathological response (p = 0.010).

CONCLUSION

Patients who respond to NAT likely have a favourable disease biology and will progress well following resection. It is these patients who should be selected for more aggressive upfront management, and those with resistant disease should be spared from high-risk surgery.

Increased rates of cetuximab reactions in tick prevalent regions and a proposed protocol for risk mitigation

BACKGROUND

Cetuximab is an anti-epidermal growth factor receptor mouse-human chimeric monoclonal antibody used to treat advanced colorectal cancers. Initial data suggest that severe infusion reactions occurred in 4.5%, many on first exposure. The majority of those with anaphylactic reactions possess predeveloped IgE antibodies to galactose-alpha-1,3-galactose. It is thought that the vector for preexposure to alpha-gal is antigen inoculation via tick bites. This retrospective study reviews the experience of two community cancer centers in high tick exposure areas in Sydney with cetuximab anaphylaxis and proposes a protocol to avoid this.

METHOD

Severe cetuximab infusion reactions occurring in the Northern Cancer Institute Frenchs Forest and St Leonards clinics, Sydney, from May 2014 to February 2019 were recorded. Area of residence was then compared to areas of known high tick prevalence.

RESULTS

A total of 87 patients received cetuximab in this period. Six patients (6.9%) experienced at least a grade 3 reaction, three females, age range 41-72 years (median 57.5 years). All were receiving cetuximab for metastatic colorectal cancer and their anaphylaxis occurred with the first infusion in all cases.

CONCLUSION

These cases support the existing theory of increased rates of cetuximab anaphylaxis in areas of high tick prevalence. Given this, we recommend the following protocol for patients being considered for cetuximab therapy: known mammalian meat allergy as an absolute contraindication; all patients receiving cetuximab should have RAST (ImmunoCAP^® ) testing for alpha-gal specific-IgE-specific antibodies before first infusion and those who test positive to be considered alternate therapy.

Why pathologists and oncologists should know about tumour-infiltrating lymphocytes (TILs) in triple-negative breast cancer: an Australian experience of 139 cases

The presence of increased tumour infiltrating lymphocytes (TILs) is established as a positive prognostic factor in triple-negative breast cancer (TNBC). The majority of studies have examined the role of TILs in predicting response to chemotherapy, but their role as a general prognostic marker in TNBC is unclear. Moreover, there is a lack of consensus in the literature regarding a suitable cut-off point by which to stratify patients into prognostic groups. Therefore, we sought to confirm the prognostic value of TILs in an independent cohort of unselected TNBCs, and to determine an appropriate cut-off point by which to stratify TIL scores into prognostically significant categories. We used the International TILs Working Group (ITWG) methodology to assess the density of stromal TILs in our cohort of 139 TNBC patients undergoing curative resection at our institution. The percentage TILs scores were categorised first into three groups: low (0-10%), intermediate (15-50%), and high (55-100%). A second binary variable was also created by separating cases into low TILs (≤50%) and high TILs (>50%) groups. Using the three-tiered system, mean disease-free survival was 156, 99 and 94 months for the high, intermediate and low TILs groups, respectively (p=0.030). However, no statistically significant improvement was observed for overall survival. Using the two-tiered system, statistically significant improvements in both overall survival (p=0.030) and disease-free survival (p=0.010) were observed. This survival benefit remained statistically significant in multivariate analyses (p=0.010, p=0.014). We conclude that TILs scored using the ITWG system and dichotomised at a cut-off score of 50%, are a powerful predictor of all-cause and disease-free survival in TNBC regardless of chemotherapy treatment.

IMMU-04. TEMPORAL AND SPATIAL MODULATION OF THE IMMUNE RESPONSE OF THE MURINE GL261 GLIOMA TUMOUR MICROENVIRONMENT

INTRODUCTION

Glioma is a debilitating and early fatal cancer arising in the glial cells of brain. Glioblastoma, the most aggressive form of gliomas, has a 5-year survival rate of 5% with treatment options limited to surgery, radiotherapy or chemotherapy with temozolomide.

OBJECTIVE

While radiation and immunotherapies are routinely studied in the murine Gl261 glioma model, little is known about its inherent immune response. In this study we quantified the temporal and spatial localisation of immune cell populations and mediators during glioma development.

METHODS

Mice were inoculated with 1x106 Gl261 cells at AP0.1mm, ML1.0mm, DV2.6mm Bregma. Tumour morphology, local and systemic immune cell populations were assessed at Day-0, 1, 3, 7, 14, and 21 post-inoculation by MRI, immunohistochemistry for Ki67+ proliferation and CD31+ vessel density; local immune infiltrate by multiplex immunofluorescence (VECTRA®;PerkinElmer); systemic immunity in spleen, bone marrow and peripheral blood by 16-parameter flow cytometry (LSRFortessa™;BD Biosciences); and multiplex immunoassay (Bio-Plex®;Bio-Rad) for plasma cytokines/chemokines.

RESULTS

From Day-3 tumours were distinguishable with high Ki67+ (> 30%) and increased tissue vascularisation (26.38±1.45 vessels/field; p< 0.05). Ki67 remained high until Day-21 with visible necrotic regions, increased vessel density and lumen area within tumour region. Increasing tumour proliferation/malignancy and vascularisation were associated with significant temporal changes in immune cell populations within the tumour (p< 0.05) and systemic compartments (p=0.02- p< 0.0001). Of note, at Day-14 NK, M1, PMN-MDSCs and M-MDSCs in the tumour infiltrate declined, coinciding with a decrease in 16/24 plasma cytokine/chemokines levels. Tumour infiltrating immune cell populations did not correlate with peripheral blood populations. However, a decrease in plasma cytokine/chemokine levels may indicate ‘immune exhaustion’.

CONCLUSIONS

The data derived provide baseline characteristics to study changes associated with multi-modal treatment strategies and to sequence therapies to maintain immune modulation. This information will contribute to the identification of novel combination therapies.

A data-driven, knowledge-based approach to biomarker discovery: application to circulating microRNA markers of colorectal cancer prognosis

Recent advances in high-throughput technologies have provided an unprecedented opportunity to identify molecular markers of disease processes. This plethora of complex-omics data has simultaneously complicated the problem of extracting meaningful molecular signatures and opened up new opportunities for more sophisticated integrative and holistic approaches. In this era, effective integration of data-driven and knowledge-based approaches for biomarker identification has been recognised as key to improving the identification of high-performance biomarkers, and necessary for translational applications. Here, we have evaluated the role of circulating microRNA as a means of predicting the prognosis of patients with colorectal cancer, which is the second leading cause of cancer-related death worldwide. We have developed a multi-objective optimisation method that effectively integrates a data-driven approach with the knowledge obtained from the microRNA-mediated regulatory network to identify robust plasma microRNA signatures which are reliable in terms of predictive power as well as functional relevance. The proposed multi-objective framework has the capacity to adjust for conflicting biomarker objectives and to incorporate heterogeneous information facilitating systems approaches to biomarker discovery. We have found a prognostic signature of colorectal cancer comprising 11 circulating microRNAs. The identified signature predicts the patients' survival outcome and targets pathways underlying colorectal cancer progression. The altered expression of the identified microRNAs was confirmed in an independent public data set of plasma samples of patients in early stage vs advanced colorectal cancer. Furthermore, the generality of the proposed method was demonstrated across three publicly available miRNA data sets associated with biomarker studies in other diseases.

Retrospective cohort analysis of neoadjuvant treatment and survival in resectable and borderline resectable pancreatic ductal adenocarcinoma in a high volume referral centre

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a deadly disease. Neoadjuvant therapy (NA) with chemotherapy (NAC) and radiotherapy (RT) prior to surgery provides promise. In the absence of prospective data, well annotated clinical data from high-volume units may provide pilot data for randomised trials.

METHODS

Medical records from a tertiary hospital in Sydney, Australia, were analysed to identify all patients with resectable or borderline resectable PDAC. Data regarding treatment, toxicity and survival were collected.

RESULTS

Between January 1 2010 and April 1 2016, 220 sequential patients were treated: 87 with NA and 133 with upfront operation (UO). Forty-three NA patients (52%) and 5 UO patients (4%) were borderline resectable at diagnosis. Twenty-four borderline patients received NA RT, 22 sequential to NAC. The median overall survival (OS) in the NA group was 25.9 months (mo); 95% CI (21.1-43.0 mo) compared to 26.9 mo (19.7, 32.7) in the UO; HR 0.89; log-ranked p-value = 0.58. Sixty-nine NA patients (79%) were resected, mOS was 29.2 mo (22.27, not reached (NR)). Twenty-two NA (31%) versus 22 UO (17%) were node negative at operation (N0). In those managed with NAC/RT the mOS was 29.0 mo (17.3, NR). There were no post-operative deaths with NA within 90-days and three in the UO arm.

DISCUSSION

This is a hypothesis generating retrospective review of a selected real-world population in a high-throughput unit. Treatment with NA was well tolerated. The long observed survival in this group may be explained by lymph node sterilisation by NA, and the achievement of R0 resection in a greater proportion of patients.

Dual Somatostatin Receptor/FDG PET/CT Imaging in Metastatic Neuroendocrine Tumours: Proposal for a Novel Grading Scheme with Prognostic Significance

Background: PET scans using FDG and somatostatin receptor imaging agents have both been used to study neuroendocrine tumours. Most reports have documented the sensitivity and specificity of each radiopharmaceutical independently, and even suggested the superiority of one over the other for different grades of disease.

Aim: The aim of this work was to develop a grading scheme that describes the joint results of both the FDG and somatostatin receptor imaging PET scans in staging subjects with neuroendocrine tumours in a single combined parameter. The grading scheme that has been developed is referred to as the NETPET grade.

Methods: This is a retrospective study which assessed subjects who had both FDG and somatostatin receptor PET imaging at our institution within 31 days of each other. The NETPET grade was assigned by experienced nuclear medicine physicians and compared with other clinical data such as WHO grade and overall survival.

Results: In the period 2011-2015 we were able to recruit 62 subjects with histologically proven metastatic neuroendocrine tumour for review. The NETPET grade incorporating both the FDG and somatostatin receptor imaging results was significantly correlated with overall survival by univariate analysis (p=0.0018), whereas in this cohort the WHO grade at the time of diagnosis did not correlate with survival.

Conclusions: The NETPET grade has promise as a prognostic imaging biomarker in neuroendocrine tumours. It permits the capturing of the complexity of dual radiotracer imaging in a single parameter which describes the subjects' disease and is readily amenable to use in patient management and further research.

Anti-inflammatory effects of sodium butyrate on human monocytes: potent inhibition of IL-12 and up-regulation of IL-10 production

Cytokines are critical in regulating unresponsiveness versus immunity towards enteric antigens derived from the intestinal flora and ingested food. There is increasing evidence that butyrate, a major metabolite of intestinal bacteria and crucial energy source for gut epithelial cells, also possesses anti-inflammatory properties. Its influence on cytokine production, however, is not established. Here, we report that butyrate strongly inhibits interleukin-12 (IL-12) production by suppression of both IL-12p35 and IL-12p40 mRNA accumulation, but massively enhances IL-10 secretion in Staphylococcus aureus cell-stimulated human monocytes. The effect of butyrate on IL-12 production was irreversible upon the addition of neutralizing antibodies to IL-10 or transforming growth factor b1 and of indomethacin. In anti-CD3-stimulated peripheral blood mononuclear cells, butyrate enhanced IL-10 and IL-4 secretion but reduced the release of IL-2 and interferon-g. The latter effect was in part a result of suppressed IL-12 production but also a result of inhibition of IL-12 receptor expression on T cells. These data demonstrate a novel anti-inflammatory property of butyrate that may have broad implications for the regulation of immune responses in vivo and could be exploited as new therapeutic approach in inflammatory conditions.

Suppression of primary T-cell responses and induction of alloantigen-specific hyporesponsiveness in vitro by the Janus kinase inhibitor tyrphostin AG490

BACKGROUND

Tyrphostin AG490 has recently been shown to block interleukin (IL)-2 receptor gamma-chain-associated Janus kinase 3. Here, we analyzed the effect of AG490 on T-cell alloresponses in vitro.

METHODS

For the evaluation of T-cell activation, DNA synthesis, surface marker expression, cytokine secretion, intracellular calcium mobilization, early protein tyrosine phosphorylation, and apoptosis were measured.

RESULTS

AG490 effectively inhibited T-cell proliferation in human mixed lymphocyte culture (MLC) even when added 4 days after culture initiation. Inhibition of IL-2-dependent proliferation in T-cell blasts and the incapability of IL-2 or IL-15 to restore proliferation in AG490-treated MLC suggests interference with cytokine receptor signaling. T-cell receptor-triggered early protein tyrosine phosphorylation, calcium mobilization, up-regulation of CD69, and initial CD25 expression were not affected. Interestingly, AG490 substantially inhibited production of IL-2 and interferon-gamma in T cells stimulated with alloantigen or via CD3 and CD28. In CD28-independent activation models (e.g., stimulation with phorbol myristate acetate plus ionomycin), however, cytokine secretion was not inhibited. Pretreatment of primary MLC with AG490 resulted in substantial down-regulation of secondary responses to cells from the original donor as opposed to third-party cells or phytohemagglutinin. Unresponsiveness was induced also in T cells stimulated with CD3 monoclonal antibody. Induction of apoptosis in polyclonally activated T cells and the incapability of IL-2 to reverse specific hyporesponsiveness, suggest programmed cell death as an important mechanism underlying antigen-specific down-regulation of alloresponses.

CONCLUSIONS

We demonstrate that AG490 blocks different manifestations of T-cell activation. This and its ability to induce alloantigen-specific hyporesponsiveness point to a potential use for interfering with alloreactivities in vivo.